Electric furnace.



No. 761,920. I 4 PATENTED JUNE 7, 1904. G. P. E. SCHNEIDER.

ELECTRIC FURNACE.

APPLICATION mum own, 1903.

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PATENTED JUNE 7, 1904.

C. P. E. SCHNEIDER. ELECTRIC FURNACE.

APPLICATION FILED 001212, 1903.

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PATBNTED JUNE 7, 1904.

0. P. E. SCHNEIDER. ELECTRIC FURNACE.

-.APPLIOATION FILED, 00T.12, 1903 s sums-sum. a.

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UNITED STATES Patented June '7, 1904.

PATENT OFFICE.

ELECTRIC FURNACE.

' SPECIFICATION forming part of Letters Patent No. 761,920, dated June7, 1904.

Application filed October 12, 1903. Serial No. 176,719. (No model.)

To all 1071/0777, it may concern.-

Be it known that 1, CHARLES PROSPER EU- GENE SCHNEIDER, of Le Creusot,Sa6ne-et- Loire, France, have invented certain new and usefulImprovements in Electric Furnaces; and I do hereby declare the followingto be a full. clear, and exact description of the invention, such aswill enable others skilled in the art to which it ap pertains to makeand use the same.

My invention relates to electric furnaces, and more particularly to thatclass of furnaces known as "induction-furnaces, in which heat isproduced by the influence of an external alternating magnetic field.

Heretofore it has been usual to employ in these furnaces annularcrucibles of approximately uniform section in which the molten metalnaturally assumes its level, leaving a considerable space between thecover of the crucible and its surface. The result of this approximatelyuniform section of the ring of molten metal is great conductivity, andconsequently the production of an extremely intense secondary inducedcurrent forming around the magnetic core a number of ampere-turns out ofproportion with that necessary in order to insure eflicient electricaloperation of the whole. The reaction of this current upon the primarycoil produces an unfavorable phase displacement of the primary current.

The improvement which forms the subject of the invention permits ofobviating these defects and, further, of obtaining the advantageshereinafter set forth.

The invention is based upon the idea of imparting great resistance tothe molten metallic circuit by constituting it by a tube of smallsection communicating at its two extremities with a melting-pot orcrucible of large dimensions containing the greater part of the moltenmetal. Then, as with this arrangement it might happen that only themetal in the tube became heated, sufiicient inclination is given to thetube as a whole to insure the production between the tube and themeltingpot of an active circulation of the metal under the influence ofthe difference of density which invariably exists between the hotter andthe cooler particles of the molten metal. The tube is thus quitefull ofmetal under slight pressure, and the surface of the metal is free onlyin the basin or crucible communicating with the tube, and the metal ofthe melting-pot constantly enters the tube by one of its orifices andleaves it heated through the other, the two orifices beng alwaysimmersed in the metal of the melting-pot. Several tubes may be employedwith one or more melting-pots.

Certain mechanical expressions of the inventive idea involved are shownin the accompanying drawings, which are designed merely as illustrationsto assist in the description of the invention and not as defining thelimits thereof.

Figure 1 shows a form of furnace consisting of a melting-pot incommunication with two heating-tubes. Fig. 2showsa modification inwhich-two 111elting-pots aroused. Figs. 3, L, and 5 show othermodifications of the furnace. Fig. 6 is a vertical section showing theapplication of the invention to a blast-furnace.

Fig. 7 is a section on line A B of Fig. 6. Fig

8 is a detail View of a portion of the apparatus shown in Fig. 2. Fig. 9is a sectional plan of a multiple-chamber regenerative furnace of theSiemenss type, taken on the line S T of Fig. 10. Fig. 10 is a verticalsection of the same on the line C D E F of Fig. 9. Fig. 11 is a verticalsection of part of the apparatus shown in Fig. 9 on theline G H IJ butreversed. Fig 12 is a longitudinal section on the line H L of Fig. 13,showing a practical constructional form of a furnace employedexclusively as an electrical furnace. Fig. 13 is a sectional plan of thesame on the line M N O P of Fig. 12; and Fig. 14L is a transversesection of the furnace shown in Fig. 12, taken on the line QR. Referringto the drawings, Figure 1 shows diagrammatically a circular melting-potin communication with two U form heatingtubes 1 and 2, slightly inclinedin such a manner that their communications 0 and f with the melting-potare at different levels. Through each loop formed by the tubes 1 2passes a magnetic frame or iron core 6, carrying a primary winding 0,traversed by the alternating current coming from dynamo 11, wherebymagnetic lines of force are produced in the iron core 6.

In the construction shown in Fig. 2 two melting-pots c are connected bythe circulation and heating tubes 3 and at. In addition a U-shaped tube1 2 heats one of the meltingpots. The induced currents are produced bythe magnetic frames or cores 6 7), provided with wimlings a, the frameand winding being shown in detail in Fig. 8.

In Figs. 3, 4, and 5 the melting-pot is shown as taking an irregularform in cross-section. Theheating tubes or conduits 1 2 are formed bythe walls a of the melting-pot itself and those of an annular false"partition 7'. Branches of these conduits are surrounded by the magneticcores 0 7/, provided with windings c. A duplicate form of melting-potshown in Fig. 5, where the two pots (4 a are connected by a narrowedconduit, in which is located an annular partition f, the walls of which,with those of the conduit, form additional heating-tubes 3 4;. Thesetubes are also surrounded by suitable cores and coils, as shown in theother forms. The circulation of the molten material is effected in asimilar manner to that in Figs. 1 and 2, where circulation takes placeunder the influence of the difference of density between the hotter andthe cooler parts of the molten bath.

in Figs. (3 and '7 is illustrated a blast-furnace, the crucible (L ofwhich is provided with the heating-tubes 1 and 2, the tubes of which areformed, as in Figs. 3, 4, and 5, partly by the walls of the crucible andthose of the inner circular partition. The crucible (L thus receives asupplementary amount of heat arising from the heat developed byinduction in the tubes 1 and 2. it is therefore possible to supplyadditional heat to the furnace through the agency of an electric currentprimarily derived from such source of power as a waterfall or even amotor actuated by the blast-furnace gases.

As an additional illustration of the application of my invention 1 haveshown it in Figs. 9, 10, and 11 in combination with amultiplechamberregenerative furnace of the Siemenss type adapted to serve, for example,for the economical manufacture of pig steel. In Figs. 9, 10, and 11, aand 5/ are the two chambers of the furnace, into which open at e and f,respectively, the branches 1 and 2 of the V-shaped heating-tube, whichis provided with the magnetic heating-cores b 7).

In one of the chambers a coke or coal of any suitable kind is placedupon an initial bath of cast-metal filling the two chambers a and z andthe tubesl and 2 of the furnace. The coke may be accumulated in a troughor hopper surmounting the chamber. The carbon of this coke or coaldissolves in the molten metal and spreads to the chamber r owing to theextremely active circulation of the metal throughout the entire furnacedue to the auxiliary heating furnished by the tubular portion 1 2.

Into the chamber (j, which is covered by an arch, ore and the necessaryliuxes are introduced by a suitable distributer supplying them in auniform manner. This ore fuses in contact with the bath and is reducedby the carbon, which it contains in solution in order to give iron,which dissolves in the initial molten-metal bath and gas charged withcarbonic oxid, which becomes liberated from the bath. The scoriaresulting from the fusion of the gangue and mixed with a certainquantity of fused ore is continuously or periodically conducted into thecompartment 1/ through the passage a, which connects the twocompartments (1' and and which consequently contains an upper layer ofscoria. This passage may be sufficiently high in vertical section topermit the gases which are produced in small quantities above the metaland in contact with the pieces of coke of the chamber a to be liberatedfreely in the chamber g. The scoria is in contact with the coke, thecindcrs of which it dissolves and which removes its last traces of iron.\Vhen it has been impoverished, this scoria is run through a pouringholea of the chamber a.

The carbonic oxid liberated may be utilized for heating the chamber Itis burned at its formation above the bath by highly-heated air inrecuperation-chambers v', comprising stacks of bricks communicating withthe chamber by the conduits /I.. Each chamber coinmunicates with aconduit Z, connected to a chimney 0. The two conduits Z' Z' are causedto terminate at a door or damper which directs the smoke of one chamberto the chimney, while it permits of the admission to the other of thecold air enteringthrough the ori- [ice in. By periodically reversing thecircuit of the gases by means of the door cold air may be caused toenter the lower part of a chamber, where it burns the carbonic oxid,which is liberated by the bath, to which may be added by way of theconduits x the small amount of gas which is produced in the column ofcoke. The products of combustion pass into the second chamber g, whichit heats, and then passes to the chimney. \Vhen the chambers haveoperated in this manner for a certain time, the gaseous current isdiverted by actuating the door-damper. In this manner a high temperatureis produced beneath the arch of the chamber which facilitates the fusionof the ore and its partial attack by the carbonic oxid, which traversesit in rising from the bath through the mass. The combination of themethod of the attack of the ore by the car bon dissolved in the metalwithout any mixture of solid carbon with the ore with the electricfurnace comprising tubes and several chambers and the heating of asingle chamber by the combustion of the carbonic oxid by means of IIOair-heated by recuperation-chambers of the Siemens type is absolutelynovel. The electric energy employed is utilized principally in order tocompensate the losses of heat and may be greatly reduced by carefulconstruction of the envelops of the furnaces in such a manner as toretain the heat as much as possible.

I prefer that the orifice c be situated slightly above the orifice f, soas to cause the carbureted metal to circulate from the chamber a towardthe chamber g through the passage 8.

Figs. 12, 13, and M illustrate myim provement applied in an exclusivelyelectric'furnace. The heating-tubes 1 2 are shown at one side of thefurnace-chamber a and communieating therewith at e and f. The tubes areprovided with suitable heating-cores and coils 0 Z). The furnace, withits heating-tubes, is supported upon a table or platform provided withadjustable supports 5, 6, and 7 Two of said supports may be made in theform of screw-jacks, thus permitting of inclining the table or platform,and consequently the furnace. This construction permits the usualfurnace operations to be carried on while the heating-tubes 1 and 2 areconstantly full of metal and consequently under pressure.

In Fig. 12 is shown a suitable tapping means 5 6, with a receptacle 7,mounted on a truck 8. Apipe 9 supplies air to the distributing chamber10, from whence it passes through twycrs 11 into chamber a. The furnaceis also provided with tap-hole 12 and lip 13, through which the contentsmay be poured by manipulating the adjustable support 7 WV hat I claimis 1. In combination, a chamber for holding molten metal, one or morepipes communicating with said chamber so constructed as to permitcirculation of molten metal, an iron core encircling said pipe or pipes,and means for producing lines of force in said core.

2. In combination, a chamber for holding molten metal, one or more pipescommunicating with said chamber so constructed as to permit circulationof the molten metal, an iron core encircling said pipe or pipes andprovided with a primary coil, and means for passing an alternatingcurrent through said coil.

3. In combination,a heating-chamber,a conduit leading from and returningto said chamber, the ends of said conduit being located at differentlevels, an iron core engaging said conduit, and means for producingmagnetic lines of force in said core.

4:. In combination, a plurality of chambers for containing molten metal,one or more pipes connecting said chambers, an iron core encircling oneor more of said pipe or pipes, and means for producing magnetic lines offorce in said core.

5. In combination, a chamber for holding molten metal, a pipe leadingfrom and returning to said chamber adapted for conducting molten metaland adjustable means for tilting the furnace-chamber whereby the linejoining the outlet and inletof said pipe may be thrown out of thehorizontal plane.

In Witness whereof I have hereunto set my hand in presence of twowitnesses.

CHARLES PROSIER EUGENE SCHNEIDER.

Witnesses:

JEAN GAMET, Gnonens BOURETTE.

